2020 Volume 74 Issue 1 Pages 251-257
In this study, focusing on the difference in the thermal characteristics between the healthy and corrosion rebar, we investigated the condition of the corrosion rebar inside the concrete from the change in surface temperature after cooling the concrete. Dry ice, which is easily available, was used as the refrigerant. Cooling with dry ice produced a cooling effect equivalent to that of liquid nitrogen （－40 to －30℃） used in previous studies. In addition, it was confirmed that the temperature of the reinforcing bar dropped when the surface was cooled. Therefore, a cooling experiment was conducted in a room with a temperature of 20 degrees and a humidity of 60％, using a specimen with corroded reinforcing bars embedded in it. As a result of the experiment, it was confirmed that the corrosion state of the rebar affects the temperature change of the concrete surface after cooling. Therefore, an estimation formula expressing the relationship between corrosion thickness and surface temperature change was created. It was found that the corrosion state of the rebar can be estimated by fitting this estimation formula and the test results. Moreover, the validity of the test was shown by comparing the analysis result by FEM and the experimental result.
